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PubMed1982

[Squint operation in presbyopic patients].

Since it is well known that the eye musculature undergoes degenerative alterations in old age, the question arises whether squint operations are effective in presbyopic and elderly persons. Twenty-four patients with horizontal squint (average age 63 years) wanted the operation because of diplopia, asthenopia and, in a few cases, for cosmetic reasons; 5 patients were aphakic. The operation was successful in 20 cases. The principles of dosing the operation are essentially the same as for juvenile patients. However, specific difficulties in treating elderly patients arise from: (1) lack of accommodative convergence, as a result of which the squint angle difference between distance and near fixation is usually greater; (2) increasing rigidity of the eye muscles, which diminishes the range of fusion; as a result, the patient is unable spontaneously to compensate for minor squint deviations; (3) senile organic lesions of the bulbs further impair fusion. It is advisable to treat convergent squint by correcting the average deviation between distance and near fixation, preferably shortening the external recti. Cases of divergent squint should preferably be treated by correcting the smaller squint angle, with resection of the external recti. The older the patient is and the worse his fusion, the more precisely the operation has to be dosed. Orthoptic training helps in old patients too.

Age Factors↗
PubMed2003

Clinical features predictive of successfully weaning from spectacles those children with accommodative esotropia.

PURPOSE: It has been reported that most children with accommodative esotropia are not able to discontinue spectacle wear as they become older. We conducted a prospective study to determine which factors are predictive of successfully weaning children from spectacles. METHODS: Beginning in 1995, children with fully accommodative esotropia with a baseline refractive error of + 1.50 to + 5.00 diopters (D) were gradually weaned from their hyperopic correction. Patients with amblyopia or who had previously undergone strabismus surgery were excluded. Children were weaned in 0.50 D increments until spectacles were discontinued or they developed esotropia, asthenopia, or decreased vision. A multivariate analysis was performed to assess the association between successful weaning and various clinical characteristics. RESULTS: Twelve of 20 children (60%) were successfully weaned from spectacles. Spectacles were prescribed at a mean age of 4.2 +/- 1.5 years, and weaning was initiated at a mean age of 8.0 +/- 1.1 years. The spherical equivalent of the least hyperopic eye when spectacles were prescribed was 2.99 +/- 1.06 D. The clinical characteristic most clearly associated with successful weaning was the refractive error at the time glasses were prescribed. Whereas 10 of 11 (91%) patients with < 3 D of hyperopia were weaned from spectacles, only 2 of 9 (22%) patients with 3 to 5 D of hyperopia were successfully weaned from their spectacles (P =.005). CONCLUSIONS: Many children with fully accommodative esotropia can be weaned out of spectacles during the grade school years. The degree of baseline hyperopia appears to be one of the best predictors of success.

Accommodation, Ocular↗
PubMed1983

Saccadic intrusions contributing to reading disability: a case report.

Horizontal eye movements were recorded during tracking and reading in a patient with probable neurological involvement who complained of periods of oscillopsia and severe asthenopia, especially during reading. Saccadic intrusions occurred during all tracking tasks. Single and multiple saccadic intrusions found while reading, frequently accompanied periods of visual disturbance, and we attribute part of the reading disability to the presence of such abnormal eye movements. Various therapeutic measures were attempted and achieved some degree of success.

Adult↗
PubMed1987

Tonic adaptation in symptomatic and asymptomatic subjects.

Tonic accommodation and tonic vergence were measured in symptomatic and asymptomatic subjects before, during, and after 45 min of binocular reading at near (5 D). Reading produced significant increases in both tonic levels, with the magnitude of change being similar in the two groups. After reading, both groups exhibited rapid loss of the tonic vergence effect, but showed no evidence for decay of the tonic accommodation effect. Differences between the groups were observed in the rate of adaptation during the course of reading, with both tonic components increasing more slowly for the symptomatic subjects than for the asymptomatic subjects. In addition, baseline tonic accommodation was significantly higher in the symptomatic group than in the asymptomatic group. The results suggest that although the failure to undergo tonic oculomotor adaptation is not a causal factor in asthenopia, the initial steady-state level and/or subsequent temporal changes of tonic accommodation and tonic vergence may be related to nearwork symptomatology.

Accommodation, Ocular↗
PubMed2005

Blink rate decreases with eyelid squint.

PURPOSE: We hypothesize that eyelid squint inhibits blink rate. This is part of a larger hypothesis that, because eyelid squint improves vision under conditions of optical defocus and/or glare, and reduced blink rate is assumed to contribute to dry eye symptoms, eyelid squint is part of the mechanism resulting in asthenopia. This study investigates the effect of voluntary eyelid squint on blink activity and on electromyography (EMG) measures from the orbicularis oculi. METHODS: Ten subjects (18 to 38 years of age) performed 3 1-minute trials each (Latin Square order) of voluntary target squint levels of 5%, 20%, 35%, and 50% with respect to previously demonstrated 0% (relaxed) and 100% (maximum) squint levels. EMG recordings using surface electrodes were obtained from the orbicularis muscle. Vertical dimension of the palpebral fissure and eye lid blinks were measured with an ISCAN eye tracker and video recorder. RESULTS: Each target squint level produced significant changes (p<0.0001) in ocular aperture size, EMG power, and EMG amplitude. For target voluntary squint levels of 5%, 20%, 35%, and 50%, the mean squint responses were 24%, 35%, 42%, and 53%, respectively. Blink rate was inversely related to both target squint level and squint response (p<0.0001), decreasing from 15 blinks per minute at 0% squint to 7.5 blinks per minute at 5% target voluntary squint and to 4 blinks per minute at 50% target voluntary squint. CONCLUSIONS: Voluntary eyelid squint significantly reduces blink rate by an average of 50% or more dependent on attempted level. Further study is required to determine if involuntary squint causes the same. All tested levels of voluntary squint resulted in an EMG signal from the orbicularis muscle that is measurably different from resting state. This indicates that EMG can be used as a reliable indicator of eyelid squint.

Adult↗
PubMed1988

The effect of optical defocus on the accommodative accuracy for chromatic displays.

Blur, probably arising from focusing inaccuracies, has been cited in ergonomic and vision literature as one of the causes of visual stress and decreased task efficiency in operation of video display units (VDUs). With the advent of colour coding in electro-optical displays, the need for a detailed quantification of focusing responses to chromatic stimuli is particularly important because of the influence of the chromatic aberration present in ocular optics on the focusing response of the eye. In this regard, we used a computer-aided laser speckle optometer system to measure the accommodative responses of 20 visually normal subjects, to brightness-matched monochromatic and multichromatic stimuli displayed on a high-resolution RGB monitor. We also investigated the effect of target size, target clarity, and viewing distance on the response accuracy of the focusing system of the eye. Our results show that while the accommodative responses are systematically influenced by target chromaticity, they are relatively independent of target size. There was no evidence of any anomalous focusing responses resulting from either target chromaticity or defocus that could account for the asthenopia frequently reported by VDU users. Furthermore, moderate levels of optical defocus did not drive accommodation into any visible hunting pattern for optimal focus or towards its tonic resting position. Implications of these findings in display designs are presented.

Accommodation, Ocular↗
PubMed1995

Sensory adaptations in Duane's retraction syndrome.

Knowledge of the sensory status of patients with Duane's retraction syndrome is limited. Fourteen patients with type A Duane's retraction syndrome, aged 6 to 22 years, were assessed prospectively and their sensory findings and the nature of their sensory symptoms detailed. All 14 patients had corrected monocular Snellen acuities of 6/9 or better. Six patients were asymptomatic and 5 of these had dense suppression on lateral versions, were free of diplopia and had variable stereopsis. The 5 bilateral cases were among the asymptomatic group. The remaining 8 patients had weak or absent suppression on lateral versions, variable horizontal diplopia and relatively normal stereopsis. Six were aware of diplopia but were never bothered by it and two spontaneously complained of symptoms related to abnormal binocularity (diplopia in one and asthenopia at near in both). It was not [corrected] possible to differentiate the 2 symptomatic cases from the former 6 on the basis of their sensory findings. Patients with type A Duane's retraction syndrome spontaneously complained of symptoms related to abnormal binocularity. The patients least likely to suffer sensory symptoms were bilateral cases or patients with dense suppression on lateral versions, irrespective of their stereoacuity levels.

Adaptation, Ocular↗
PubMedDate not supplied

Ocular motility in Parkinson's disease.

INTRODUCTION: Parkinson's disease is associated with multiple abnormalities of both the afferent and efferent visual systems. Blepharospasm, paucity of blinking, apraxia of lid opening, visual neglect, reduced vergence, reduced upgaze, and blurred vision are reported findings in these patients. The association of these findings with the disease, and their duration, severity, and treatment have not been systematically investigated. PATIENTS AND METHODS: Patients with Parkinson's disease were prospectively examined. An age-matched control group was recruited from accompanying family members and volunteers. Data recorded included presence of visual complaint, the severity of the Parkinson's disease by Hoehn and Yahr Stage (scale = 1 to 5), duration of disease, pharmacologic therapy, visual acuity, ocular motility, accommodation, convergence amplitudes, and the near point of convergence. RESULTS: Thirty-nine patients were entered into each group, each with 21 men and 18 women. The average patient had had the disease for 8.9 years with a severity index of 2.6. Asthenopia, upgaze deficiency, and convergence insufficiency were significantly more common in the patients with Parkinson's disease than in the controls. Mean geometric visual acuity was poorer in the Parkinson's patients (20/39 compared with 20/28); P < .001). DISCUSSION: Visual complaints were significantly more common in the Parkinson's patients than in the age-matched controls. The frequency of ocular abnormalities was not related to the duration of the disease. Increasing severity seemed to be correlated with the presence of convergence insufficiency and a decline in acuity.

Accommodation, Ocular↗
PubMedDate not supplied

A systematic review of the applicability and efficacy of eye exercises.

PURPOSE: To examine the current scientific evidence base regarding the efficacy of eye exercises as used in optometric vision therapy. METHODS: A search was performed of the following databases: Allied and Complementary Medicine Database, Cochrane Database of Systematic Reviews, Cochrane Register of Controlled Trials, EMBASE, and MEDLINE. Relevant articles were reviewed and analyzed for strengths and weaknesses. Pertinent sections of classic texts were studied to provide a historical basis and to serve as a source for additional early references. RESULTS: Forty-three refereed studies were obtained. Of these, 14 were clinical trials (10 controlled studies), 18 review articles, 2 historical articles, 1 case report, 6 editorials or letters, and 2 position statements from professional colleges. Many of the references listed by the larger reviews were unpublished or published in obscure or nonrefereed sources and therefore were not accessible. CONCLUSIONS: Eye exercises have been purported to improve a wide range of conditions including vergence problems, ocular motility disorders, accommodative dysfunction, amblyopia, learning disabilities, dyslexia, asthenopia, myopia, motion sickness, sports performance, stereopsis, visual field defects, visual acuity, and general well-being. Small controlled trials and a large number of cases support the treatment of convergence insufficiency. Less robust, but believable, evidence indicates visual training may be useful in developing fine stereoscopic skills and improving visual field remnants after brain damage. As yet there is no clear scientific evidence published in the mainstream literature supporting the use of eye exercises in the remainder of the areas reviewed, and their use therefore remains controversial.

Exercise Therapy↗
PubMedDate not supplied

Three-year results of photorefractive keratectomy for myopia.

We evaluated the results of single-step photorefractive keratectomy (PRK) on 35 consecutive myopic eyes (19 patients) with follow up of 3 years or more. The range of preoperative myopia was from -2.00 diopters (D) to -6.00 D with astigmatism of less than 1.50 D. The excimer laser used in this study was the ExciMed UV 200LA, (Summit Technology), which was set to a maximum correction of -6.00 D at a 5.0-mm diameter ablation zone. Uncorrected visual acuity better than 20/25 was achieved in 82.9% of eyes. Spectacle corrected visual acuity was equal to or better than that of preoperative levels in 94.3%. The difference between attempted and achieved correction was within 1.00 D in 60.0% of eyes. The myopic regression curve was Y = 3.679-0.6876 log (X). If the regression remains constant, we expect that refraction at 5 years after PRK would be -1.48 D. Trace corneal haze was present in 12 eyes (34.3%). At three years the most common subjective complaint was mild decreased night vision with asthenopia. The findings suggest that myopic regression can occur as long as 3 years after PRK.

Adult↗
PubMedDate not supplied

LASIK for high myopic astigmatism resulting from perforating ocular injury.

PURPOSE: To present a case of successful treatment of high myopic astigmatism after a perforating injury with significant corneal laceration and pupil ectopia using excimer LASIK. METHODS: A 30-year-old man presented for treatment of high myopic astigmatism in his right eye resulting from perforating ocular trauma, which occurred 8 years prior to presentation. The corneoscleral wound repair was performed with posterior chamber intraocular lens implantation. Uncorrected visual acuity (UCVA) in the right eye was counting fingers at 1 m, best corrected to 20/30 with -7.00 + 5.00 x 110. Visual acuity in the left eye was 20/20 with -1.5 D. The patient was unable to tolerate spectacles and contact lenses because of asthenopia and high astigmatism, respectively. As an alternative, LASIK with the Allegretto Wave excimer laser was performed. RESULTS: Three months postoperatively, UCVA was 20/25 in the right eye and 20/15 in the left eye. CONCLUSIONS: This case indicates that LASIK can be a useful surgical method for correcting high myopic astigmatism resulting from ocular trauma with significant corneoscleral laceration.

Adult↗
PubMed1989

[Post-operative cyst and orbital walls: a CT image analysis].

A set of coronal CT images obtained by 118 side (109 cases) of post-operative cysts of maxilla, seen from 1982 to 1988, was analyzed as to the orbital wall affections. Coronal images were grouped into five consecutive planes, i.e. the first plane being the one which is 5mm posterior to the nasion, and the other planes in successive orders each being 5mm apart. The orbital walls were classified into inferior, medial, and transition of these two. The orbital wall affections were classified into dehiscence, thinned-out (less than 1mm), and normal. The orbital signs and symptoms (epiphora, pain, asthenopia, visual loss, diplopia, and exophthalmos) were analyzed based upon the questionnaires by patients. The inferior wall affections (dehiscence and thinned-out) were seen most often (57%) at the third plane (2cm posterior to the nasion). The orbital signs and symptoms in general were seen in half of the cases of which 20% were of grave (visual loss, diplopia and exophthalmos). These signs and symptoms were the more often, the more anterior the site of affections located. Grave signs and symptoms were seen at 2 to 2.5cm posterior to the nasion when the orbital floor was affected and the inferior rectus were either pushed up or in direct contact with the cysts.

Adolescent↗
PubMed1999

Efficacy of vision therapy for convergence insufficiency in an adult male population.

BACKGROUND: Although vision therapy has reportedly been very successful in elimination of asthenopic symptoms in adults with convergence insufficiency, controlled studies have not been performed, and a clinical bias exists against prescribing vision therapy for adults with convergence insufficiency. METHODS: Sixty adult males over the age of 40 years (median age, 65 years) with convergence insufficiency were divided into three treatment groups: office-based vision therapy with supplementary home therapy, home therapy only, and a control group. RESULTS: Vision therapy was successful in 61.9% of patients who received in-office plus home therapy, in 30% of patients who received home therapy only, and in 10.5% of the control group. The success rate for patients who received active in-office vision therapy supplemented with home procedures was significantly greater than that for controls. Home therapy alone was less successful than in-office therapy. The success rate obtained with home therapy alone was not significantly greater than that demonstrated by controls. CONCLUSIONS: Vision therapy is effective in eliminating asthenopia and improving convergence function in adult patients. In-office therapy combined with home therapy tends to produce better results than does home therapy alone.

Adult↗
PubMed1999

Symptomatic aniseikonia in unilateral and bilateral pseudophakia. A projection space eikonometer study.

PURPOSE: To determine the incidence of aniseikonia and aniseikonic symptoms in pseudophakia (intraocular lens implantation after cataract extraction). METHOD: Aniseikonia, stereoacuity, and clinical symptoms were evaluated in patients with unilateral and bilateral pseudophakia. Aniseikonia was determined with the Essilor projection space eikonometer. Eight-seven cases were studied, fifty-four of unilateral pseudophakia and thirty-three of bilateral pseudophakia. Nine of the 87 patients had insufficient stereopsis to be examined or measured for aniseikonia with the Essilor instrument, and were studied with the "Double-D", a two dimensional "direct comparison eikonometer" device programmed and viewed on a computer. Stereoacuity was determined with the Titmus Stereo Test. RESULTS: Thirty-five (40.2%) of all pseudophakes had ophthalmic complaints referable to aniseikonia. The mean aniseikonia in the unilateral pseudophakia group was 4.1%, SD=3.41, while the mean aniseikonia in the bilateral group was 3.2%, SD=2.6. CONCLUSION: Symptomatic aniseikonia is common in pseudophakia. Unilateral pseudophakia has the higher degrees of aniseikonia, and is at a greater risk of loss of binocularity and of asthenopia.

Adult↗
PubMed2000

Test-retest reliability of the College of Optometrists in Vision Development Quality of Life Outcomes Assessment.

BACKGROUND: Medical diagnoses such as headaches, diplopia, nausea, and asthenopia are conditions that are often treated with optometric vision therapy. Improvement of such subjective conditions after a regimen of therapy is often difficult to objectively quantify. The goal of this study was to verify the test-re-test reliability of a new clinical survey instrument, the College of Optometrists in Vision Development (COVD) Quality of Life Outcomes Assessment, which allows the analysis of symptoms data. METHODS: The first-year class of optometry students at the Oklahoma College of Optometry at Northeastern State University were administered the instrument in a group setting on two different occasions, two weeks apart. Nineteen students completed both test and re-test. Statistical analysis by the Wilcoxon Signed Rank Test and paired t test were performed. RESULTS: Each subject reported some of the 30 symptoms on both test and re-test. The instrument was found to be reliable. Wilcoxon Signed Rank Analysis showed no significant differences in test-retest scores, either pooled or item-by-item. A paired t-test group and item analysis were insignificantly different between scores. Spearman's rho correlation for test-retest of each subject was 0.878. Eighty-nine percent (17 of 19) scored insignificantly different between administrations. Ninety percent of the items (27 of 30) were found to vary insignificantly between the two administrations. CONCLUSIONS: The COVD Quality of Life Outcomes Assessment is a reliable tool to measure changes in symptoms on the basis of optometric intervention--specifically, vision therapy.

Humans↗
PubMed2001

Vergence adaptation in children and its clinical significance.

BACKGROUND AND PURPOSE: Vergence adaptation has not been well investigated in children even though it may contribute to binocular dysfunction and near work induced asthenopia. METHODS: We compared vergence adaptation in 18 children and 18 young adult subjects by assessing tonic vergence (TV) before and immediately after a period of sustained near fixation, by measuring heterophoria with a synoptophore through 0.5 mm binocular pinholes. Adaptation was induced by a reading task at 15 cm for a continuous 5 minute period. RESULTS: Mean pre-task TV values of 0.70 MA (Meter Angles) and 0.20 MA were observed for the children and young adults, respectively (p = 0.08). The initial mean vergence adaptation for children and adults was +0.45 MA and +0.11 MA, respectively (p = 0.001). CONCLUSION: The greater vergence adaptation observed in children may impact upon the clinical assessment of their binocular vision, especially heterophoria measurement which may require longer periods of dissociation than previously recommended, and might also ultimately be partly responsible for the predominant development of esodeviations during childhood

Adaptation, Ocular↗
PubMed2002

[Ophthalmic manifestations of masticulatory system dysfunctions].

Temporomandibular joint dysfunctions may involve ophthalmic symptoms such as orbital pain, asthenopia, or anisocoria. These ophthalmic manifestations may be the first signs or the complications of masticatory system dysfunctions. Treatment of these ophthalmic symptoms begins with treatment of the temporomandibular joint dysfunctions.

Eye Diseases↗
PubMed2003

Evaluation of a new direct-comparison aniseikonia test.

BACKGROUND AND PURPOSE: Aniseikonia is a condition in which the two eyes perceive images of different size or shape, causing a variety of visual symptoms including asthenopia. Besides anisometropes (with a prevalence of 5-10% in the population above age 20 years), also pseudophakes and refractive surgery patients are at risk. For example, 40% of the pseudophakes seem to suffer from aniseikonia. Reliable measurement and management of aniseikonia is therefore important. The "Aniseikonia Inspector" is a new, commercially available, software product to measure and manage aniseikonia. The purpose of this study is to evaluate this aniseikonia test of the Aniseikonia Inspector. METHODS: Aniseikonia was induced in four subjects, with normal vision, by means of afocal size lenses. Using the Aniseikonia Inspector, the resulting aniseikonia was measured in vertical, horizontal and diagonal directions. RESULTS: The average ratio between the measured aniseikonia and the induced aniseikonia was 0.98, 0.89 and 0.93 respectively for the vertical, horizontal and diagonal directions. For two consecutive measurements of the same aniseikonic state, the difference in measurement value was 97%, 75% and 94% of the time within one resolution step size (0.5% horizontally and vertically, and 0.7% diagonally). CONCLUSION: Aniseikonia was measured accurately. Measurements in the vertical direction were more accurate than in the diagonal or horizontal directions, which is probably due to fixation disparities. The Aniseikonia Inspector is a very useful new tool in treating the growing number of aniseikonia patients.

Adult↗